But especially at this point, I’m on a mission to get as many people using Holosync® as I possibly can—my current goal is 100 million Holosync® users. Because we already have so many people using it, the economy of scale allows me to offer it to you for MUCH less than what my accountant suggested: just $179 if you’d like Awakening PrologueTM on CDs… or $159 if you want the downloadable MP3 version…
There are many sources of binaural beats on the internet and YouTube to check-out and experiment with yourself – I recommend using headphones for optimal effectiveness. However, like most things, not all binaural beats are created equally (especially if they are free on the internet) and therefore not as effective or enjoyable to listen to. This is why I HIGHLY recommend the binaural beats created by master audio technician, music producer and meditation teacher, Cory Allen – which can be found here:

It is a good idea to follow any instructions outlined by the makers of any type of brainwave entrainment product or program, and to ease yourself carefully into using it. If experiencing any negative side effects, take a break and come back to it later. Brainwave entrainment audios are not recommended for children under the age of 18, and should not be used while driving or operating heavy machinery.

Many psychologists, doctors, teachers, and other professionals have endorsed the technology while personally taking advantage of the limitless benefits that accompany EquiSync's precisely designed brainwave synchronization/ entrainment technology. It is such a profound field of study that many of the metaphysical benefits, those beyond our current scientific measure and technological & philosophical understanding, have yet to be discovered.
Changes in neural oscillations, demonstrable through electroencephalogram (EEG) measurements, are precipitated by listening to music,[20][21][22][23][24][25] which can modulate autonomic arousal ergotropically and trophotropically, increasing and decreasing arousal respectively.[26] Musical auditory stimulation has also been demonstrated to improve immune function, facilitate relaxation, improve mood, and contribute to the alleviation of stress.[27][28][29][30][31][32][27][33] These findings have contributed to the development of neurologic music therapy, which uses music and song as an active and receptive intervention, to contribute to the treatment and management of disorders characterized by impairment to parts of the brain and central nervous system, including stroke, traumatic brain injury, Parkinson's disease, Huntington's disease, cerebral palsy, Alzheimer's disease, and autism.[34][35][36]
Hi Julie! You’re very welcome for the info. In answer to your question, I think some are probably good, and some not so good. There are many people putting brainwave entrainment out there these days and it is not so easy to figure out which ones are and aren’t of reliable quality without investing time and doing some research. I would say (in general) that paid products are probably better quality than free ones, but I couldn’t guarantee this is a golden rule. My best advice is to just do your research before spending too much time listening to the freebies.
So on thursday 21st July 2018 I tried marisa peers audio. She has a program that I bought that was just hypnosis audios. I then got three bonus audios. One of them was called money-wiring hypnosis typnaral alpha brainwave audios, which I tired for the first time. As soon as I went into hypnosis I had a weird sensation and my whole head and body stared stimulating to a point where I felt like I couldn’t really move. I thought maybe it was just me being more relaxed. Until I started to feel pain on the side of my head near my ear. I woke up after and went to bed thinking it will get better the next day. But woke up with a headache feeling sick and tingling and numbness near my head and jaw. I contacted them and they said it’s just blood going to your brain but now I feel tingling around my body and pain in my head and ears. I don’t really know what to do but team responsible for this hasn’t heaven me good answer since it hasn’t really gotten better. I feel on edge and losing energy. Please can some one advise.

Brainwave entrainment is a colloquialism for such 'neural entrainment', which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of an external stimuli, such as a sustained acoustic frequency perceived as pitch, a regularly repeating pattern of intermittent sounds, perceived as rhythm, or of a regularly rhythmically intermittent flashing light.